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‘Afourer’ mandarins were stored in air containing ethylene at 0.001, 0.01, 0.1, and 1 μL L −1 at 20, 10, 5 and 0 °C and changes in a range of external and internal quality parameters were examined for up to 10 weeks in storage. At all storage temperatures, reducing ethylene concentration in the storage environment decreased the rate of respiration, visible deterioration of the calyx region, ethanol accumulation in the juice, loss of eating quality, and at chilling temperatures reduced rind pitting. The quality attributes limiting mandarin storage life differed between the different storage temperatures but retention of mandarin quality was always optimised by maintaining the lowest possible ethylene atmosphere around fruit. Thus, the primary target should be to ensure the ethylene levels are ≤0.01 μL L −1 , as loss of quality was accelerated above this concentration. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is a kind of carcinogen, which can interfere with the body’s endocrine system. In this paper, a new kind of fluorescent sensor for BPA detection was established based on the fluorescent conjugated polymer PPESO 3 . The oxidative product of BPA is able to quench PPESO 3 in the presence of HRP and H 2 O 2 , and the quenched PL intensity of PPESO 3 was proportionally to the concentration of BPA in the range of 1–100 μmol/L with a detection limit of 4 × 10 −7 mol/L. The proposed method has been applied to detect BPA in eight food packaging samples with satisfactory results. The proposed method has the potential for the assay of BPA in food or food packaging samples. [ABSTRACT FROM AUTHOR]

• A wearable gloved probe based on Ag nanoparticles and rare earth. • A sensitive, efficient, and reliable method for TC sensing. • Ultrafast POCT detection of TC in various water and food samples. • Real-time rapid visual intelligent analysis of TC. The abuse of tetracycline antibiotics leads to accumulating residues in the human body, seriously affecting human health. Establishing a sensitive, efficient, and reliable method for qualitative and quantitative detection of tetracycline (TC) is necessary. This study integrated silver nanoclusters and europium-based materials into the same nano-detection system to construct a visual and rapid TC sensor with rich fluorescence color changes. The nanosensor has the advantages of a low detection limit (10.5 nM), high detection sensitivity, fast response, and wide linear range (0–30 μM), which can meet the analysis requirements of different types of food samples. In addition, portable devices based on paper and gloves were designed. Through the smartphone's chromaticity acquisition and calculation analysis application (APP), the real-time rapid visual intelligent analysis of TC in the sample can be realized, which guides the intelligent application of multicolor fluorescent nanosensors. [ABSTRACT FROM AUTHOR]

Highlight • This review focuses on recent trends for arsenic speciation analysis in mushrooms. • We summarize the contents and distribution of arsenic species in mushrooms. • Methods of arsenic speciation analysis are systematically reviewed. • Purification, concentration and stability of arsenic species are briefly reviewed. Abstract Owing to the strong concentration and biotransformation of arsenic, the influence of some edible mushrooms on human health has attracted widespread attention. The toxicity of arsenic greatly depends on its species, so the speciation analysis of arsenic is of critical importance. The aim of the present review is to highlight recent advances in arsenic speciation analysis in edible mushrooms. We summarized the contents and distribution of arsenic species in some edible mushrooms, the methods of sample preparation, and the techniques for their identification and quantification. Stability of the arsenic species during sample pretreatment and storage is also briefly discussed. [ABSTRACT FROM AUTHOR]

• A novel multicolor probe based on Zif-8 and rare earth. • Realization of TC visual detection with high recognition. • Ultrafast POCT detection of TC in various water and food samples. • Combined application of gelled detection device and intelligent APP. In this work, a high-precision visual and point-of-care testing (POCT) ratiometric fluorescent nanosensor for TC was constructed by embedding fluorescein (FL) into l -histidine modified ZIF-8 (LZIF-8) and chelating with rare earth citrate complex. Upon exposure to TC, the coordination and energy transfer between Eu3+ and TC make Eu3+ sensitized emission characteristic red fluorescence, while without prejudice to the emission peak intensity of FL. This ratiometric fluorescent probe with stable reference signal had the characteristics of high sensitivity (ultralow LOD = 5.99 nM) and selectivity and fast response kinetics (within 20 s). The high-bright fluorescence emission was beneficial to human eye recognition and it can realize semi-quantitative detection of TC in eggs, meeting the requirements of household use. In addition, the color can be read and analyzed quickly with the help of smart phone color analysis APP, and the semi-quantitative concentration of TC can be determined more conveniently. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel multi-color fluorescent FA sensing system was meticulously designed. • It possesses the capability of fluorometric and colorimetric dual-mode FA sensing. • Visual detection of FA by wearable glove-based film sensor. • The design of logic gates promotes the development of FA intelligent devices. Excess formaldehyde (FA) is a strong carcinogen, so the development of a rapid visualized and portable formaldehyde detection platform is of great research importance. A multi-color fluorescence sensing system constituted of model compound (NAHN) and red-emitting InP/ZnS QDs was constructed herein, which can simultaneously realize fluorometric-colorimetric dual-mode sensing when exposed to FA environment. Its preparation process was simplified, the detection process was green, and the limits of detection (LOD) were 0.623 μM and 0.791 μM, respectively. The high recoveries of FA in actual water samples indicated that the sensor had broad application prospects. The prepared fluorescent film can be utilized for rapid visual simulation analysis of FA on the surface of various fruits and vegetables. In addition, a serial logic gate was designed to quickly semi-quantitatively assess FA concentration, which promoted the realization of on-site intelligent evaluation of FA. [ABSTRACT FROM AUTHOR]

• • A colorimetric sensor array based on peroxidase activity nanoenzymes was constructed. • • Eight tea polyphenols in Tieguanyin were successfully distinguished. • • Effective identification of Tieguanyin and adulterated tea. • • Effectively identify Tieguanyin of different harvesting seasons. • • Successfully identified autumn tea with different degrees of adulteration. Tieguanyin (TGY) is one of top ten famous teas in China, but in the process of brand building there is the phenomenon of falsehood, thus harming the interests of consumers. To solve the adulterate problem of TGY, a colorimetric sensor array (CSA) based on peroxidase activity of nanozyme was constructed. Nanozymes can catalyze 3,3′,5,5′-tetramethylbenzidine (TMB) to 3,3′,5,5′-tetramethyl -[1,1′-bis(cyclohexyl)]-2,2′,5,5′-tetraene-4,4′-diimine (oxTMB), while the tea polyphenols (TPs) can inhibit this process, and the degree of inhibition varies significantly with the reaction time. We selected two nanozymes and three reaction time points to construct CSA. It can successfully distinguish TPs in TGY. The discriminative analysis can achieve: (1) distinction between TGY and adulterated tea, (2) discrimination of TGY in various seasons and seasonal adulteration in different degrees. The method constructed in this work is promising for both the class and quality differentiation of TGY and other teas with TPs as the main activity. [ABSTRACT FROM AUTHOR]

• ICP-MS/MS O 2 mode was applied to eliminate interferences in determination of arsenic. • Ultrasonic extraction with ultrapure water ensured the stability of arsenic species. • Most wild edible mushrooms tested contained only non-toxic organic arsenic species. • Inorganic arsenic in some tested mushrooms were relatively high. Some varieties of edible mushrooms can accumulate high contents of arsenic, which is a public health concern. In this study, we developed a high-performance liquid chromatography method linked to inductively coupled plasma triple quadrupole mass spectrometry (HPLC-ICP-MS/MS) for sensitive and accurate determination of arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenocholine and arsenobetaine in edible mushrooms. The six arsenic species were extracted ultrasonically from mushrooms using ultrapure water at 60 °C as the solvent, separated on a PRP-X100 anion exchange column (4.1 × 250 mm, 10 µm), with 20 mmol/L NH 4 HCO 3 and 50 mmol/L (NH 4) 2 CO 3 as the mobile phase, and quantified using ICP-MS/MS in the oxygen reaction mode. The linear range of the method was 0.5 µg/L–100 µg/L with detection and quantification limits of 2.5 µg/kg–10 µg/kg (S/N = 3), and 8 µg/kg–33 µg/kg (S/N = 10), respectively. This method was applied successfully to the detection and speciation of arsenic in eight varieties (266 samples) of mushrooms. Our results indicated that most wild edible mushrooms contained organic arsenic, mainly arsenobetaine and arsenocholine. However, the inorganic arsenic content of Armillariella tabescens (3.63 mg/kg) and parts of the cultivated Agaricus blazei murrill (up to 4.50 mg/kg) were relatively high, which is potential risk to the health of consumers. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel sensor array was built by 4 laccase-like nanozymes for OPs distinction. • OPs identification was not interfered by CPs, metal ions, or antibiotics. • Smartphone-assisted portable method was proposed for OPs on-site analysis. Accurate pesticide identification is of great importance for regulating food safety. However, the discrimination between organophosphorus pesticides (OPs) and carbamate pesticides (CPs) is still a challenge for existing analytical methods based on cholinesterase inhibition. It mainly because of the similar inhibitory effect of OPs and CPs on cholinesterase. Herein, we found that OPs and CPs differentially affected nanozymes with laccase-like activity, which would be interfered by OPs in different degrees rather than CPs. Thus, we fabricated a nanozyme sensor array and successfully achieved the OPs identification and similar individual discrimination, ignoring the interference from CPs or other potential interferents (antibiotics, ions, other pesticides). On the basis of nanozyme sensor array, a portable method using smartphone was constructed and utilized to determine OPs in fruits and vegetables. This work would contribute to the development of portable sensors and the highly selective identification and discrimination of OPs in complex samples. [ABSTRACT FROM AUTHOR]

Highlights • A novel method for the sensing of H 2 O 2 and choline was developed. • The detection was based on near infrared luminescent UCNPs. • The upconversion luminescence was quenched to 3% of its original intensity by Fe3+. • UCNPs can avoid the interference of fluorescent substances in complex samples. Abstract Choline is an essential nutrient for the growth and development of the baby, and therefore it is often added to infant formula. In this paper, a novel sensor for choline determination in infant formula is developed based on upconverting nanoparticles (UCNPs) with near infrared luminescence. UCNPs-based detection can avoid the interference of background fluorescence from complex samples, and thus provide high selectivity and sensitivity. It was observed that in the presence of Fe3+, polyacrylic acid coated UCNPs were quenched to 3% of its original intensity. The degree of quenching was among the best for UCNPs. Hydrogen peroxide could oxidize Fe2+ to Fe3+, which caused quenching of the upconversion luminescence. A new H 2 O 2 detection method was thus established. In addition, choline could be hydrolyzed to betaine by choline oxidase, and at the same time produced H 2 O 2 , which also caused luminescence quenching through Fe2+ oxidation. Therefore, selective choline sensing was achieved. [ABSTRACT FROM AUTHOR]

Highlights • A novel method for the sensing of adenosine triphosphate was developed. • The detection was based on S1 nuclease, FAM-labeled ssDNA and graphene oxide. • The method was applied to the evaluation of meat freshness. Abstract A novel simple, sensitive and reliable sensor based on S1 nuclease, FAM-labeled ssDNA (DNA-F) and graphene oxide (GO) was developed for detecting adenosine triphosphate (ATP) and evaluating the freshness of meat (beef) samples. With S1 nuclease as the cleaver of DNA-F and ATP as the inhibitor of S1 nuclease, the fluorescence of DNA-F could be obviously quenched by GO, which exhibits the fluorescence of system gradually decrease as the increasing ATP concentration. Under the optimal conditions, a linear correlation between the fluorescence and the ATP concentration from 20 μM to 3500 μM is obtained with a detection limit of 3.2 μM. Furthermore, the proposed ATP detection method was applied to the ATP detection in microorganisms in meat samples, which acquired the satisfying results, respectively. [ABSTRACT FROM AUTHOR]

A novel approach for rapid identification of three foodborne pathogens including Staphylococcus aureus , Vibrio parahaemolyticus and Shigella sonnei in foods by solid phase microextraction (SPME) coupled with gas chromatography–mass spectrometry (GC–MS) was established. After cultivation 24, 18 and 20 h for Staphylococcus aureus , Vibrio parahaemolyticus and Shigella sonnei , respectively, the microbial volatile organic compounds (MVOCs) were extracted with a SPME device equipped with divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) coated fibers. The DB-1701P column was applied for separation of MVOCs. A total of 17, 13 and 14 volatile organic compounds were identified as characteristic MVOCs of Staphylococcus aureus , Vibrio parahaemolyticus and Shigella sonnei , respectively. Similarity of the MVOC chromatographic fingerprints for the bacteria were calculated and compared, and the results showed that the established method is stable, reproducible, accurate and has the potential to identify the three bacteria in food samples. [ABSTRACT FROM AUTHOR]

• Storage of 'Comte de Parisʼ pineapple fruit at 10 °C reduced internal browning as compared to storage at 25 °C. • Increased the levels of PL, UFA/SFA and IUFA were associated with less internal browning in fruit stored at 10 °C. • Accumulations of PA, LPE, and PLAs were correlated with internal browning tolerance in fruit stored at 10 °C. To uncover the mechanism underlying membrane lipid metabolism of low temperature induced internal browning tolerance in pineapple, membrane phospholipid alterations of harvested 'Comte de Paris' winter pineapple fruit stored at either 10 °C or 25 °C was investigated. Fruit stored at 10 °C developed low levels of internal browning as compared to fruit stored at 25 °C and was associated with high contents of phosphatidylcholine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, and phosphatidylethanolamine, and low levels of phosphatidic acid. Storage at 10 °C down-regulated the expression levels of phospholipase As. Fruit stored at 10 °C also exhibited high ratio of unsaturated fatty acid to saturated fatty acid and index of unsaturated fatty acid level. These findings suggest that maintenance phospholipid abundance, reduction in phosphatidic acid accumulation and membrane lipid peroxidation may have contributed to the enhanced internal browning tolerance in 'Comte de Paris' winter pineapple fruit at low temperature storage. [ABSTRACT FROM AUTHOR]

• A plasma colorimetric bionic sensor for rapid, on-site detection of CAP was constructed. • Cage Au@AuNPs with excellent SPR response were utilized to construct plasma colorimetric bionic sensor. • Aptamer-based cHCR was designed to further enhance the sensitivity and specificity of CAP analysis. • The plasma colorimetric bionic aptasensor had great potential application in food analysis and environmental monitoring. A plasma colorimetric aptasensor was developed for rapid determination of chloramphenicol (CAP) in honey on site. Herein, cage gold shell@core nanoparticles (Au@AuNPs) were synthesized to enhance signal response and broaden the linear range. In addition, aptamer-based cascade hybridization chain reaction (cHCR), consisting of HP1, HP2, HP3, and HP4, was also designed for signal amplification and specific analysis. In this assay, HP1 and HP4 were immobilized on the surface of cage Au@AuNPs. In the presence of CAP, cHCR was triggered, and frond-like DNA products were formed, which made the distance among the cage Au@AuNPs closer and the system color changed from red to deep purple. Qualitative and quantitative analysis were carried out according to color changes and UV–Vis spectra. Under the optimized conditions, the wavelength of UV–Vis absorption peak exhibited a good linear relationship with CAP concentration in the range of 5.0 to 500 nmol/L with the detection limit of 1.2 nmol/L (S/N = 3). This aptasensor also showed good specificity for CAP detection compared with other antibiotics similar to the target analyte. Furthermore, the colorimetric aptasensor was successfully applied to the detection of CAP in honey with recoveries of 88.0–107.6%. This cHCR-based aptasensing for CAP possesses high sensitivity, good selectivity, low cost and excellent stability, and could be extended to detect a wide variety of other small molecular analytes, nucleic acids or proteins. Therefore, the versatile method might become a potential alternative tool in food analysis and environmental monitoring. [ABSTRACT FROM AUTHOR]

Highlights: [•] Profile and content of phenolics in leaves of 20 sweetpotato cultivars were studied. [•] Free, conjugate and total phenolics were obtained using three preparation methods. [•] Twenty-nine phenolics in samples were identified using HPLC–DAD and HPLC–ESI–MS/MS. [•] Two dihexosides and one hexoside of quercetin were first characterised. [•] Artefacts of esterification during acidic alcoholic hydrolyses were revealed. [Copyright &y& Elsevier]

• Antibiotics residues and their metabolites are serious threats to human and animal health. • Antibiotics biosensor has the advantages of rapid response and easy miniaturization. • This review covered selectivity and sensitivity with nanomaterials of antibiotics biosensors. • This review discussed future trends and perspectives of antibiotics biosensor. Antibiotics are widely used in the prevention and treatment of infectious diseases in animals due to its bactericidal or bacteriostatic action. Residual antibiotics and their metabolites pose great threats to human and animal health, such as potential carcinogenic and mutagenic effects, and bacterial resistances. Therefore, it is necessary and urgent to accurately monitor trace amounts of antibiotics in food samples. Up to now, many analytical methods have been reported for the determination of antibiotics. Biosensors with the advantages of high sensitivity, rapid response, easy miniaturization, and low price have been widely applied to the detection of antibiotics residues in past decades. This review offered an in-depth evaluation of recognition elements for antibiotic residues in diverse food matrices. In addition, it presented a systematical and critical review on signal amplification via various materials, focusing on recently developed nanomaterials. Finally, the review provided an outlook on the future concepts to help upgrade the sensing techniques for antibiotics in food. [ABSTRACT FROM AUTHOR]

• A novel sensor array is developed for the identification of milk adulteration. • The sensor array is based on perylene probe monomer-excimer emission transition. • Cationic polymer induced aggregation of a perylene probe. • The sensor array can be applied for the quantification of milk adulteration. A novel fluorescence sensor array based on cationic polymer induced self-assembly of a perylene probe is developed. Cationic polymer induced aggregation of the carboxyl modified negatively charged perylene probe, and resulted in large quenching of monomer emission and generation of excimer emission. Upon the addition of negatively charged protein, monomer fluorescence restored with a decrease in excimer fluorescence. Based on these observations, we developed a six-channel sensor array to discriminate five main proteins in milk. In addition, we successfully identified pure milk out of different drinks using the developed sensor array since different drinks contained distinct species and contents of proteins. Furthermore, the sensor array exhibited excellent performance to discriminate milk adulterated by different concentrations of adulterants with 100% accuracy of cross validation. The analysis results also presented excellent linear correlation of adulterants contents and thus the developed sensor array shows great potential for quantitative detection of milk adulteration. [ABSTRACT FROM AUTHOR]